黄冶窑白瓷的物相和微观结构研究

以黄冶窑四个时期的白瓷样品作为研究对象,利用X射线衍射仪（XRD）和扫描电子显微镜（SEM）对样品进行分析,结果表明:黄冶窑白瓷胎的物相基本相同,主要是莫来石、α石英和方石英、未熔石英和少量的粘土相;黄冶窑白瓷釉中有气泡存在,釉中气泡为圆形,釉中存在微米级的针状或柱状钙长石晶体,釉存在分相结构,且分相结构与析晶相伴而生;黄冶窑白瓷胎中有气孔、未熔的石英颗粒、较大的Ti颗粒、莫来石晶体和石英晶体。The white porcelain samples of the four periods of Huangye kiln were studied in this paper, and the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the material phase is basically the same of the white porcelain bodies from Huangye kiln, and mainly mullite, alpha quartz and cristobalite, unmelted quartz and a small amount of clay phase; There are some round bubbles in HuangYe kiln white porcelain, glazes, so are some feldspathic crystals with micro-level needles or columnar. It is evident to observe phase separation structure, which is accompanied by the birth. Apart from some pores, unfused quartz particles, larger Ti particles, mullite crystals and quartz crystals can also be found in the embryo of Huangye kiln white porcelain.     

Growth and characteristics of some new varieties of coloured quartz single crystals

Abstract

Methods for the hydrothermal synthesis of four new coloured varieties of quartz have been developed. Two of these varieties are very rare in nature. They are a bi-coloured amethyst-citrine quartz (ametrine) and a phosphorous-bearing low-temperature pink quartz. The other two varieties have no natural counterparts. They are a pink-violet Ni-bearing quartz, and a Cu-bearing quartz which resembles aventurine. The principal conditions for producing these varieties of quartz single crystals are described.     

Mössbauer studies of raw materials from Misti volcano of Arequipa (Peru) for its potential application in the ceramic field

We would like to introduce, the study of two different colour “sillar” samples: white and pink, belonging to the Añashuayco quarry in the Arequipa Region (Peru). The X-ray diffraction (XRD) analysis indicates the presence of several mineralogical phases, such as feldpars and biotite for the both white and pink “sillar” whereas cristobalite and quartz are detected only in the first sample and amorphous phase in the second one. In room temperature, Mössbauer spectroscopy, the presence of hematite (α-Fe₂O₃) was detected as the main phase for both samples, this was not detected in the XRD measurements. Moreover, corresponding doublets in the Mössbauer spectra indicate the presence of iron in the aluminium-silicate minerals. The rates Fe^2?+?/Fe^3?+? are 0.0752 and 0.0526 to the white and pink samples respectively. The minerals composing the white tuff form a heterogeneous aggregate of uniform aspect. Mining of these materials generates a great amount of waste in the form of lumps of varying size and which are raw materials studied in the present work for potential application in the ceramic field.     

Electron microscopic investigations of tracks of Cf252 fission fragments in quartz glass

Using a single stage carbon replication technique, track pits of Cf²⁵²-fission products in quartz glass could be revealed by transmission electron microscopy with a high degree of resolution. From the shape of the track pits the angles of incidence of the nuclear particles were determined down to extremely small angles. In addition track pits on the fracture surface of irradiated quartz glass samples have been investigated by scanning electron microscopy.     

A comparative study of the thermoluminescence properties of several varieties of Brazilian natural quartz

The following varieties of natural quartz, as the blue, the green, the red, the pink, the black, the sulphurous and the milky quartz, have been investigated concerning their thermoluminescence properties. For comparison sake natural colorless alpha quartz has been include. Since X-rays diffraction analysis has shown that all of them have the same crystal structure as the alpha quartz, it is expected that no great change in the TL property should be found, however, that was not the case. The TL peaks at 110, 175, 220, 325 and 375 °C observed in the alpha quartz are not found in all the varieties of quartz, for instance, the sulphurous quartz presented only 110° and 245° peaks, the pink one presented just 110, 220 and 375 °C peaks and so on. In respect to TL response as function of gamma ray dose a quite varied behavior has been observed and discussed.     

Mössbauer study of rock paintings from minas gerais (Brazil)

Four samples of a wall containing rock paintings have been studied by Mössbauer spectroscopy in combination with optical microscopy analysis and X-ray diffraction. Hematite and goethite were identified as the pigments responsible for the colors and the mineral tinsleyite, as the principal component of a light pink layer that is present in some parts of the wall.     

Dating study of two rock crystal carvings by surface microtopography and by ion beam analyses of hydrogen

Two artefacts made of rock crystal (quartz) from the collection of the Musée du quai Branly in Paris, France, a skull approximately half of the size of a real cranium and a smaller anthropomorphic head, purportedly attributed to pre-Columbian Mesoamerican cultures, were studied to assess their authenticity. The surface of the artefacts were examined by means of optical microscopy and scanning electron microscopy (SEM) and were analyzed nondestructively by ERDA (Elastic Recoil Detection Analysis), an ion beam analytical method that can measure hydrogen concentration profiles in depth. Optical and SEM imaging of tool marks indicates that the skull has been cut from a rock crystal block using machine lapidary techniques unavailable to pre-Columbian artisans, whereas the anthropomorphic head has more likely been carved and polished with manual techniques comparable to ancient ones. Hydrogen depth profiles in the first micron below the surface of the artefacts have been measured by ERDA with a 3-MeV He beam in a controlled helium atmosphere. Recently the progressive penetration of water at the surface of a quartz sample exposed to the natural environment has been proposed as a dating method (labeled quartz hydration dating or QHD) applicable to archaeological artefacts made of this material. The shallower penetration of H clearly indicates that the rock crystal skull was manufactured more recently than the reference quartz sample cut in 1740. As for the anthropomorphic head, the deep penetration profiles indicate an older artefact. Thus the converging micro-topographical examinations and hydrogen profiles of the samples surfaces indicate that the skull is probably not a pre-Columbian artefact but has been carved in the 18th or 19th century. The anthropomorphic head, on the other hand, could have been carved in the pre-Columbian period. In addition, the ERDA method carried out with an external beam presented here provides a new and simple approach for the nondestructive authentication of quartz-based archaeological artefacts by QHD.     

Synthesis and tunable luminescence properties of monodispersed sphere-like CaWO4 and CaWO4:Mo/Eu,Tb

Monodispersed CaWO₄ and CaWO₄:Mo/Eu, Tb microspheres have been obtained hydrothermally with excellent reproducibility. X-ray diffraction, field-emission scanning electron microscopy and photoluminescence were used to characterize the as-synthesized samples. The results uncover the formation process of the microspheres and the influence of ethylenediamine. Doping proper concentration of Mo into CaWO₄ micropheres can extend the excitation range as the incorporation induces obvious redshift. We have also tuned the color from blue to pink blue, white and green only by varying the relative content of Eu–Tb in the CaWO₄ host.     

Two-step synthesis of one-dimensional single crystalline GaN nanowires

Straight and smooth GaN nanowires were synthesized on quartz substrates through the direct reaction of Ga₂O₃ thin films with flowing ammonia in a horizontal oven without using a template or catalyst. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM) and photoluminescence (PL) were used to characterize the samples. The straight and smooth cylindrical nanostructures are high quality single crystalline hexagonal wurtzite GaN nanowires with diameters ranging from 5 to 30 nm and lengths up to 20 μm. The near-band-edge emission peak located at 367 nm was observed at room temperature.     

CO2激光和等离子体清洗提高石英基片损伤阈值

 采用连续CO₂激光和真空等离子体相结合的方法对石英基片进行清洗。通过光学显微图、水接触角、透过率和损伤阈值测量分别表征了CO₂激光和等离子体对真空硅脂蒸发物污染过的石英基片的清洗效果。研究表明：对于真空硅脂蒸发物污染后的石英基片，可以先采用低能量的CO₂激光进行大面积清洗，再用真空等离子体进行精细清洗。光学显微图像表明：清洗后的基片表面的油珠被清除干净；水滴接触角由63°下降到4°；在400 nm附近，基片透过率由92.3%上升到93.3%；损伤阈值由3.77 J/cm²上升到5.09 J/cm²。     

TXRF and ICP-OES analysis of liquid-phase laser-ablated (LP-LA) nanoparticles of cryolite-alumina solutions

A new procedure with minimum sample preparation has been developed for a fast and serial analysis of cryolite with varying concentrations of dissolved alumina by liquid-phase laser ablation followed by Total Reflection X-Ray Fluorescence and induced coupled plasma optical emission spectroscopy. The analysis supplies the sodium/aluminium ratio of bath samples taken from industrial Hall-Herault reduction cells, as well as trace element relative concentrations. Two different types of molten samples taken directly from the aluminium production plant were placed under distilled de-ionized water in a quartz cell and subjected to pulsed laser ablation using the beam from a third harmonic Nd:YAG laser. Scanning electron microscopy examination shows the nanoparticles nature of the ablated material. The water-suspension is deposited on quartz reflectors for Total Reflection X-ray Fluorescence analysis or directly aspirated to the induced coupled plasma yielding the aluminium and sodium signals. Instrument quantification of the elements is performed by the use of aqueous standards. Validation tests were done with cryolite sample digestion and standard methods of sample quantification. The procedure can provide the aluminium/sodium ratio with adequate precision for aluminium production plant cell diagnostics and reveals the trace elements that could be considered as contamination.     

Scientific basis of technology of fine-crystalline quartz and corundum

Abstract

Authors have investigated the mechanism and the kinetics of fine-crystalline quartz and corundum synthesis in supercritical water. The thermovaporous treatment of raw materials has been carried out in laboratory (v=20 ml) and technical (v = 2m³ and v=4m³) autoclaves at temperatures between 390 and 410°C and vapor pressures of water from 20 to 27 MPa in the presence of miacroadditives of activators. The samples of products after thermovaporous treatment have been studied by X-ray diffraction, optical and electron microscopy, mass-spectroscopy, ESR-, IR-spectroscopy, thermal analysis and pycnometry. It was shown that microadditives of activator into silica or alumina might not only accelerate the attainment of the best hydroxylation, but also initiate the transformation of precursors in an ordered way. The control of the transformation mechanism by introducing activators into the starting materials has allowed us to obtain fine-crystalline quartz and corundum with desired properties: various habitues and size of crystals. On the basis of these data, technology of fine-crystalline quartz and corundum has been developed.     

Characteristics of time-resolved luminescence in quartz

Time-resolved luminescence measurements were performed with samples of synthetic quartz (Sawyer Premium Q) and granular quartz extracted from ceramics and sediment samples under pulsed (5 ns) laser stimulation (OPO). The luminescence was detected in the UV region using colour glass filters (FWHM 280–380 nm). The time-resolved spectrum is dominated by a single exponential decay that remains substantially unaltered when the stimulation wavelength is changed from 600 to 450 nm indicating that the same recombination process is being observed. The lifetime measured at room temperature was 40±0.6 μs for the synthetic quartz; at elevated temperatures the measured lifetime is reduced in a manner that is consistent with a competitive non-radiative recombination process (thermal quenching). An average lifetime of 33±0.3 μs was obtained for seven samples of granular quartz, indicating a common recombination process in these natural samples that differs from the value for synthetic quartz.     

Cathodoluminescence Spectral Characteristics of Quartz and Feldspars in Unaltered and Hydrothermally Altered Volcanic Rocks (Almeria,Spain)

The volcanic rocks of the Cabo de Gata region have been transformed by hydrothermal alteration, forming in some areas, highly silicified and feldspatized rocks. Various samples from outcrops of unaltered and hydrothermally altered volcanic rocks were studied by conventional transmitted-light microscopy to determine their genesis (magmatic, inherited or neoformed) and scanning electron microscope cathodoluminescence to define their spectral features. The magmatic quartz shows emission bands at 400, 440, and 480nm., and these bands disappear or decrease in the secondary hydrothermal quartz, characterized also by an intense emission band at around 570–580 nm, and another around 460 nm. The inherited magmatic plagioclase and neoformed anorthoclase have some similar emission bands and their genesis is not marked by cathodoluminescence features. The magmatic K-feldspars (sanidine), have emission bands at around 425, 440, and 490 nm, constituting a strong blue emission (420–500 nm). This emission is weaker in the neoformed K-feldspars that, however, have a strong emission band at around 570 nm. These data show that some cathodoluminescence spectral characteristic can be used to determine the petrogenesis of rock.     

Fabrication of nc-Si/SiO2 structure by thermal oxidation method and its luminescence characteristics

Nano-crystalline silicon/silicon oxide （nc-Si/SiO2） structures have been prepared from amorphous silicon films on both silicon and quartz substrates by using electron-beam evaporation approach and annealing at temperatures about 600 ℃ in air. As a thermal oxidation procedure, the annealing treatment is not only a crystallization process but also an oxidation process. Scanning electron microscopy is employed to characterize the surface morphology of the nc-Si/SiO2 layers. Transmission electron microscopy study shows the sizes of nc-Si grains on the two different substrates. The nc-Si/SiO2 structures exhibit visible luminescence at room temperature as confirmed by photoluminescence spectroscopy. Comparing the photoluminescence spectra of different samples, our results agree with the quantum confinement-luminescence center model.     

Temperature dependence of luminescence time-resolved spectra from quartz

Pulsed optical stimulation of luminescence has been used to study the thermal dependence of luminescence lifetimes in quartz over the temperature range 20–200°C. Time-resolved spectra for lifetime analysis were recorded from samples of quartz over a dynamic range of 64 μs following stimulation of luminescence by pulsed 525 nm green light emitting diodes (LEDs) using an 11 μs pulse and 12% duty cycle. It has been demonstrated that an increase in measurement temperature generally leads to a decrease in lifetimes from about 30 μs at 20°C to about 7 μs at 200°C. The form of the decrease is influenced by the initial optical or thermal pre-treatment of samples.     

Aberrant thermoluminescence dates obtained from primary volcanic quartz

This study deals with the dating by thermoluminescence (TL) of quartz from six volcanic formations of the Saint Lucia Island (Lesser Antilles Arc). Quartz microcrystals up to one millimetre in size were extracted from dacites and pumice flows and prepared in a way similar to the well-known inclusion technique. The TL properties of these quartz were used to estimate apparent palaeodoses using the multi-aliquot protocol. The quartz TL was studied in three different spectral domains: red, green and ultraviolet/blue. The calculated annual dose-rates yielded a set of 18 age-estimates. For some samples complementary dates were obtained using high temperature TL (HTTL) of plagioclase feldspars. These latter dates combined with previously determined radiocarbon and unspiked K–Ar dates were used to explore the validity of ages computed from the TL of quartz. Individual values for quartz appear to be scattered and do not match ages deduced from ¹⁴C, unspiked K–Ar or HTTL on plagioclase dates. These results indicate that when conventional TL methodologies derived from the inclusion method are applied to volcanic quartz major dating problems are to be expected.     

Structural and Electronic Properties Study of Colombian Aurifer Soils by Mössbauer Spectroscopy and X-ray Diffraction

In this work a study on gold mineral samples is reported, using optical microscopy, X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The auriferous samples are from the El Diamante mine, located in Guachavez-Nariño (Colombia) and were prepared by means of polished thin sections. The petrography analysis registered the presence, in different percentages that depend on the sample, of pyrite, quartz, arsenopyirite, sphalerite, chalcopyrite and galena. The XRD analysis confirmed these findings through the calculated cell parameters. One typical Rietveld analysis showed the following weight percent of phases: 85.0% quartz, 14.5% pyrite and 0.5% sphalerite. In this sample, MS demonstrated the presence of two types of pyrite whose hyperfine parameters are δ ₁ = 0.280 ± 0.002 mm/s and Δ ₁ = 0.642 ± 0.002 mm/s, δ ₂ = 0.379 ± 0.002 mm/s and Δ ₂ = 0.613 ± 0.002 mm/s.     

Thin films of Cu(II)-o,o′-dihydroxy azobenzene nanoparticle-embedded polyacrylic acid (PAA) for nonlinear optical applications developed by matrix assisted pulsed laser evaporation (MAPLE)

Thin films based on two different metal-organic systems are developed by MAPLE and their nonlinear optical applications are explored. A complex of o,o′-dihydroxy azobenzene with Cu²⁺ cation is found to organize as a non-central symmetric crystallite. A simple protocol is developed for the in situ fabrication of highly monodisperse copper-complex nanoparticles in a polymer film matrix of polyacrylic acid. The thin films were deposited on quartz substrates by MAPLE (matrix assisted pulsed laser evaporation) using a Nd:YAG laser working at 355 nm. Atomic force microscopy (AFM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and optical second harmonic generation (SHG) were performed on the samples. The optical limiting capability of the nanoparticle-embedded polymer film is investigated.     

Investigation of optical properties of annealed aluminum phthalocyanine derivatives thin films

Semiconducting molecular materials based on aluminum phthalocyanine chloride (AlPcCl) and bidentate amines have been successfully used to prepare thin films by using a thermal evaporation technique. The morphology of the deposited films was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Studies of the optical properties were carried out on films deposited onto quartz and (1 0 0) monocrystalline silicon wafers and films annealed after deposition. The absorption spectra recorded in the UV–vis region for the as-deposited and annealed samples showed two absorption bands, namely the Q- and B-bands. In addition, an energy doublet in the absorption spectra of the monoclinic form at 1.81 and 1.99 eV was observed. A band-model theory was employed in order to determine the optical parameters. The fundamental energy gap (direct transitions) was determined to be within the 2.47–2.59 and 2.24–2.44 eV ranges, respectively, for the as-deposited and annealed thin films.